• Proceedings of the Korean Printing Society Conference
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• 1995.11a
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• pp.4-8
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• 1995

본 실험에서는 최근 급 신장된 국내신문인쇄의 윤전지절에 관해 지절발생수준 및 원인에 관해 분석하였다. 국내 신문사의 윤전지절 발생수준은 구미수준이며, 자동계지 (Autopasting)시 지절이 많았다. 전체적으로 국내 신문인쇄정비기술 및 장력수준은 양호하나 전기적친 정비기술, 신문사란 통일된 관리기법이 요구된다. 종이물성측면에서 기존의 인장, 인열강도 등의 관리로는 미소의 상관성 또는 부분상관성으로 전체적인 지절예측에는 한계가 있으며, 인열강도를 현실성있게 표현한 Fracture Toughness(FT)가 상관관계가 있음을 보여주었다. 또한 마찰계수 역시 지절상관성이 기대되는 물성임을 알 수 있었다. 윤전지절은 인쇄기의 불안정과 종이결함이 복합된 결과로 인쇄기의 안정성유지와 종이의 결함을 최소화하는 것이 필요하다. FT와 마찰계수를 이용한 관리기법으로 지료조성 및 펄프의 개질, 초지공정에 응용하여 최적강도 포인트를 찾아야 할 것이다.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.28-28
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• 2011

최근 초경량 직물에 나일론 Spiral Crimp 신축소재에 많이 사용되어지는 Mechanical 신축성 직물이 시판되고 있으나 신축특성의 저하, 품질 저하의 문제점이 대두되고 있어 아직까지 본격적으로는 상용화되지 못하고 있고 국내외적으로 아직까지 나일론 세섬사 Spiral Crimp 신축소재개발과 관련된 기술개발은 전무한 실정이다. 따라서 본 연구에서는 현재까지 국내외적으로 개발되지 못한 스포츠 아웃도어용 경량직물의 Mechanical 신축성 초경량 직물을 개발하기 위해서 중합단계에서 나일론 개질 폴리머를 개발하고, 수축 특성이 서로 다른 2종의 나일론 폴리머를 이용하여 side by side 형태로 세섬 복합방사와 사가공 및 연신 단계에서 2d급 Spiral Crimp 및 Super Bulky특성이 우수한 신축성 소재를 개발하여 이들의 구조와 물성을 조사 검토하여 이를 실제 현장에 자료를 제공하는 것을 목적으로 하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.29-36
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• 2000

This investigation has been studied about friction and wear properties which were important problem, when carbon fiber reinforced plastic(CFRP) was used practically. Unidirection carbon fiber reinforced composites was fabricated with epoxy resin matrix and carbon fiber as a reinforced, and its surface was modified by the ion-assisted reaction. And then we tested the their friction and wear properties according to the ion-irradiation. when the amount of ion-irradiation was 1${\times}$10l6$\^$16/ ions/$\textrm{cm}^2$, the friction coefficient values were about 0.1, where as, the friction coefficient values of non-treatment composites were about 0.16. The former was the stablest in wear mode. We know that ion-irradiation was not proportioned to the friction coefficient, so we found the optimal conditions of the friction and wear according to the ion-irradiation.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.140-140
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• 2012

박막제조 기술은 과학 기술의 기초가 되는 분야로 양질의 박막을 제조하기 위한 다양한 노력이 경주되고 있다. 박막제조는 표면개질과 함께 표면처리 기술의 한 분야이며 이중 진공증착으로 알려진 물리증착법과 화학증착법은 현대의 과학기술 연구는 물론 산업적으로 폭넓게 이용되는 박막제조 기술 중의 하나이다. 진공증착을 이용한 박막제조 기술은 나노 기술의 등장과 함께 비약적인 발전을 이루었으며 자연모사와 완전화 박막의 제조, 융복합 공정을 이용한 기능성 코팅과 Engineered Structure 구현 그리고 초고속 증착과 원가 저감 기술의 실현이 주요 이슈로 등장하고 있다. 본 논문에서는 물리증착법과 화학증착법을 중심으로 박막제조 기술의 종류와 원리를 설명하고 박막제조 기술의 최신 동향과 기술적 이슈 및 향후 전망에 대해 기술한다.

• Textile Coloration and Finishing
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• v.33 no.4
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• pp.258-268
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• 2021

This study conducted on the introduction of recycled cellulose fibers, which are widely used in the textile industry as eco-friendly biomass materials, into polypropylene resins, which are mainly used for interior and exterior materials such as door trims and console parts of automobiles. In general, cellulose fibers can affect mechanical properties and have a lightening effect when used as a reinforcing agent. However, since cellulose fibers have hydrophilic properties and have relatively low compatibility with industrial polymer resins, they are used in combination through fiber hydrophobic surface treatment. Therefore, through this study, the reforming reaction conditions optimized in terms of hydrophobicity and workability for cellulose fibers are studied. Furthermore, polypropylene containing surface-modified cellulose fibers was prepared to compare physical properties by fiber content and study optimized content.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.99-100
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• 2022

This study analyzed the basic characteristics of mortar using CGS modified by pretreatment. As a result of the analysis, it was found that CGS after reforming can be partially replaced with fine aggregates to solve the existing air volume reduction problem when used, and can contribute positively in terms of securing fluidity and improving strength. Therefore, it is considered necessary to verify as a functional material of CGS through concrete durability experiments as a future task.

• Polymer(Korea)
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• v.28 no.2
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• pp.154-161
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• 2004

Modified poly(4-vinylpyridine) was obtained by partial quarternization of nitrogen atoms in pyridine rings of poly(4-vinylpyridine) with methyl group. By means of laser light scattering and fluorescence, it was found that this modified polymer chains were aggregated in the aqueous solution and its structure was core-shell type. The hydrophobic parts of the chains were densely condensed in core part and the hydrophilic part of quarternized amino with positive charge formed the shell part. In the mixed system of modified poly(4-vinylpyridine) and anionic surfactant, sodium dodecyl sulfate, it was observed that a critical aggregation concentration existed and that this critical concentration was suddenly decreased above 0.1 M NaCl. The size change of aggregates was also investigated by dynamic light scattering while sodium dodecyl sulfate was added into polymer solution upto the critical aggregation concentration.

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.592-597
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• 2014

The graphite/$SiO_2$ composites as anode materials for lithium-ion batteries were prepared by sol-gel method to improve the graphite's electrochemical characteristics. The prepared graphite/$SiO_2$ composites were analysed by XRD, FE-SEM and EDX. The graphite surface modified by silicon dioxide showed several advantages to stabilize SEI layer. The electrochemical characteristics were investigated for lithium ion battery using graphite/$SiO_2$ as the working electrode and Li metal as the counter electrode. Electrochemical behaviors using organic electrolytes ($LiPF_6$, EC/DMC) were characterized by charge/discharge, cycle, cyclic voltammetry and impedance tests. The lithium ion battery using graphite/$SiO_2$ electrodes had better capacity than that of using graphite electrodes and was able to deliver a discharge capacity with 475 mAh/g at a rate of 0.1 C. Also, the capacity retention ratio of the modified graphite reaches 99% at a rate of 0.8 C.

• Elastomers and Composites
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• v.44 no.1
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• pp.34-40
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• 2009

New coupling agent or surface modified agent (9-decenoic acid) was used to enhance the compatibility between silica and polystyrene in silica/polystyrene hybrid nanocomposite, synthesized by in situ miniemulsion polymerization. Composites contain well dispersed nanosize silica particles. Related tests and analyses confirmed the success of synthesis. Functionalization of silica by 9-decenoic acid and silica on the polystyrene was confirmed by FTIR. TGA showed presence and amount of silica in final latex. The glass transition temperature of the hybrid nanocomposite was increased with the silica amount. SEM and TEM analysis showed the spherical morphology of PS and composite with an average diameter of 55 nm. The presence of silica within composite was confirmed by EDS attached to the existing TEM.

• Journal of Hydrogen and New Energy
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• v.26 no.5
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• pp.445-452
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• 2015

A tubular packed bed reactor for the steam-$CO_2$ combined reforming of natural gas to produce the synthesis gas of a target $H_2/CO$ ratio 2.0 was simulated. The effects of the reactor dimension, the feed gas composition, and the gas feeding temperature upon the possibility of coke formation across the catalyst bed were investigated. For this purpose, 2-dimensional heterogeneous reactor model was used to determine the local gas concentrations and temperatures over the catalyst bed. The thermodynamic potential distribution of coke formation was determined by comparing the extent of reaction with the equilibrium constant given by the reaction, $CH_4+2CO{\Leftrightarrow}3C+2H_2O$. The simulation showed that catalysts packed in the central region nearer the entrance of the reactor were more prone to coking because of the regional characteristics of lower temperature, lower concentration of $H_2O$, and higher concentration of CO. With the higher feeding temperature, the feed gas composition of the increased $H_2O$ and correspondingly decreased $CO_2$, or the decrease in the reactor diameter, the volume fraction of the catalyst bed subsequent to coking could be diminished. Throughout the simulation, reactor dimension and reaction condition for coking-free operation were suggested.